Explanation :
According to astronomers, the whole universe is started with a giant explosion called as Big Bang. Big Bang theory shows that the universe is extended from high density state.
There are some evidence for big bang as :
(1) There are some red shifts of different galaxies which means that the universe is expanding.
(2) Due to the expanding of universe, some of the new elements are created like hydrogen, deuterium etc.
(3) Microwaves are detected by orbiting detectors.
All this parameters shows that big bang theory was correct.
Answer:
It would be D. Proterozoic because they appeared 542 million years ago.
Answer:
It depends on their masses, and the distance between them.
Explanation:
According to Newton's Law of Universal Gravitation, every particle in the universe attracts any other particle with a strength that is directly proportional to the product of its masses and inversely proportional to the square of the distance between them. Mathematically it is expressed as:
Where:
Surface tension could be defined as the property of the surface of a liquid that allows it to resist an external force. The cohesive forces among liquid molecules are responsible for the phenomenon.
In simpler terms, it is the force that causes the molecules on the surface of a liquid to be pushed together and form a layer. The surface tension, then, is a measure of the cohesive forces that hold the molecules together.
Getting the actual measurement would give us 72 dynes/cm at 25°C . However, the force decreases significantly depending on the temperature.